Guest Post by Willis Eschenbach.
For all of its faults, the IPCC (Intergovernmental Panel on Climate Change) lays out their idea of the climate paradigm pretty clearly. A fundamental part of this paradigm is that the long-term change in global average surface temperature is a linear function of the long-term change in what is called the “radiative forcing”. Today I found myself contemplating the concept of radiative forcing, usually referred to just as “forcing”.
So … what is radiative forcing when it’s at home? Well, that gets a bit complex … in the history chapter of the Fourth Assessment Report (AR4), the IPCC says of the origination of the concept (emphasis mine):
The concept of radiative forcing (RF) as the radiative imbalance (W m–2) in the climate system at the top of the atmosphere caused by the addition of a greenhouse gas (or other change) was established at the time and summarised in Chapter 2 of the WGI FAR [First Assessment Report].
Figure 1. A graph of temperature versus altitude, showing how the tropopause is higher in the tropics and lower at the poles. The tropopause marks the boundary between the troposphere (the lowest atmospheric layer) and the stratosphere. SOURCE
The concept of radiative forcing was clearly stated in the Third Assessment Report (TAR), which defined radiative forcing as follows:
The radiative forcing of the surface-troposphere system due to the perturbation in or the introduction of an agent (say, a change in greenhouse gas concentrations) is the change in net (down minus up) irradiance (solar plus long-wave; in Wm-2) at the tropopause AFTER allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values.
In the context of climate change, the term forcing is restricted to changes in the radiation balance of the surface-troposphere system imposed by external factors, with no changes in stratospheric dynamics, without any surface and tropospheric feedbacks in operation (i.e., no secondary effects induced because of changes in tropospheric motions or its thermodynamic state), and with no dynamically-induced changes in the amount and distribution of atmospheric water (vapour, liquid, and solid forms).
So what’s not to like about that definition of forcing?
Well, the main thing that I don’t like about the definition is that it is not a definition of a measurable physical quantity.
We can measure the average surface temperature, or at least estimate it in a consistent fashion from a number of measurements. But we can never measure the change in the radiation balance at the troposphere AFTER the stratosphere has readjusted, but with the surface and tropospheric temperatures held fixed. You can’t hold any part of the climate fixed. It simply can not be done. This means that the IPCC vision of radiative forcing is a purely imaginary value, forever incapable of experimental confirmation or measurement.
The problem is that the surface and tropospheric temperatures respond to changes in radiation with a time scale on the order of seconds. The instant that the sun hits the surface, it starts affecting the surface temperature. Even hourly measurements of radiative imbalances reflect the changing temperatures of the surface and the troposphere during that hour. There is no way that we can have the “surface and tropospheric temperatures and state held fixed at the unperturbed values” as is required by the IPCC formulation.
There is a second difficulty with the IPCC definition of radiative forcing, a practical problem. This is that the forcing is defined by the IPCC as being measured at the tropopause. The tropopause is the boundary between the troposphere (the lowest atmospheric layer, where weather occurs), and the stratosphere above it. Unfortunately, the tropopause varies in height from the tropics to the poles, from day to night, and from summer to winter. The tropopause is a most vaguely located, vagrant, and ill-mannered creature that is neither stratosphere nor troposphere. One authority defines it as:
The boundary between the troposphere and the stratosphere, where an abrupt change in lapse rate usually occurs. It is defined as the lowest level at which the lapse rate decreases to 2 °C/km or less, provided that the average lapse rate between this level and all higher levels within 2 km does not exceed 2 °C/km.
This is an interesting definition. It highlights that there can be two or more layers that look like the tropopause (little temperature change with altitude), and if there is more than one, this definition always chooses the one at the higher altitude.
In any case, the issue arises because under the IPCC definition the radiation balance is measured at the tropopause. But it is very difficult to measure the radiation, either upwelling or downwelling, at the tropopause. You can’t do it from the ground, and you can’t do it from a satellite. You have to do it from a balloon or an airplane, while taking continuous temperature measurements so you can identify the altitude of the tropopause at that particular place and time. As a result, we will never be able to measure it on a global basis.
So even if we were not already talking about an unmeasurable quantity (radiative change with stratosphere reacting and surface and tropospheric temperatures held fixed), because of practical difficulties we still wouldn’t be able to measure the radiation at the tropopause in any global, regional, or even local sense. All we have is scattered point measurements, far from enough to establish a global average.
This is very unfortunate. It means that “radiative forcing” as defined by the IPCC is not measurable for two separate reasons, one practical, the other that the definition involves an imaginary and physically impossible situation.
In my experience, this is unusual in theories of physical phenomena. I don’t know of other scientific fields that base fundamental concepts on an unmeasurable imaginary variable rather than a measurable physical variable. Climate science is already strange enough, because it studies averages rather than observations. But this definition of forcing pushes the field into unreality.
Here is the main problem. Under the IPCC’s definition, radiative forcing cannot ever be measured. This makes it impossible to falsify the central idea that the change in surface temperature is a linear function of the change in forcing. Since we cannot measure the forcing, how can that be falsified (or proven)?
It is for this reason that I use a slightly different definition of the forcing. This is the net radiative change, not at the troposphere, but at the TOA (top of atmosphere, often taken to mean 20 km for practical purposes).
And rather than some imaginary measurement after some but not all parts of the climate have reacted, I use the forcing AFTER all parts of the climate have readjusted to the change. Any measurement we can take already must include whatever readjustments of the surface and tropospheric temperatures that have taken place since the last measurement. It is this definition of “radiative forcing” that I used in my recent post, An Interim Look at Intermediate Sensitivity.
I don’t have any particular conclusions in this post, other than this is a heck of a way to run a railroad, using imaginary values that can never be measured or verified.
w.
Ocean heating: The Coriolis affect combined with surface obstacles and currents define the major components of Earth’s unique oceanic fluid dynamics. Ocean layers are heated, especially around the equatorial belt, with IR heating (not long wave) which itself is filtered to various levels at the surface because of cloud variation. The heat absorbed by the oceans is then mixed and sloshed around or allowed to sit and layer calmly via trade wind variations.
Oceanic heat loss: My educated guess is that in various ways, heat is largely released back into the atmosphere, sometimes because of storms, and usually because of its eventual trip to the poles where it evaporates and eventually escapes the confines of our planet. Some years and decades (long and short) the oceans lose a lot of heat, and some years and decades that cooling system doesn’t work so well. This gain/loss see-saw is anything but predictable.
I think longwave radiation oceanic heating (the kind that is re-emitted from the ocean and re-emitted back into the ocean from the atmosphere) is a tiny player, buried in the noise, in the above description, and certainly not at all in measurable trends.
Phi replied to me: “Well, science is not the stock market! Either radiative forcing has a meaning, or it does not.”
The IPCC’s definition of radiative forcing provides a very clear meaning. Radiative forcing is the result of a calculation that determines how the net flux of radiation through the atmosphere is expected to change as the atmosphere and/or the radiation entering the atmosphere changes. The IPCC has specified where (the tropopause) and how (allow stratosphere to reach radiative equilibrium) that calculation is to be done, and their choices make sense. To do the calculations, one needs carefully measured parameters from many reproducible laboratory experiments, atmospheric conditions and composition, and how much radiation enters the atmosphere from the sun, the surface and cloud tops. (All but the parameters change from location to location, so there is no single correct answer.) At least some of the software for doing these calculations is available on the Internet. If anything in climate science desires to be called “settled science”, it might be radiative forcing.
Unfortunately, “radiative forcing” reported in W/m2 doesn’t mean anything to non-specialists. The IPCC chapters that I have read about GHG forcing don’t tell the public how to interpret radiative forcing in terms of a temperature increase. Instead they wait until they have amplified radiative forcing with poorly understood feedbacks to produce climate sensitivity or processed through climate models containing parameters that have been tuned so that 20th century warming is attributed to increasing GHGs.
Here’s a reasonable interpretation of radiative forcing in terms of warming, generally called the no-feedbacks climate sensitivity. W = eoT^4, so W+dW = eo(T+dT)^4 where dW and dT are small changes, deltaW and deltaT. With a little algebra and ignoring terms with higher powers of dT, one can derive an equation I rarely encounter: dW/W = 4*(dT/T). It says that the percent change in radiation will be four times bigger than the associated percent equilibrium change in temperature (in degK). To compensate for a radiative forcing of 3.7 W/m2 (1.54% change) we need a 0.38% increase in temperature. Since the surface and lower troposphere receive about 240 W/m2 of solar radiation (after account for albedo), the equivalent blackbody temperature (255 degK) appears to be the most relevant temperature to use, affording a 1.0 degK warming. Where will this warming take place? Calculations can’t tell us, but 90% of the photons escaping to space are emitted from the upper troposphere, so a reasonable answer is that upper troposphere (where the temperature is near 255 degK) will warm 1.0 degK. If the lapse rate remains unchanged, the surface will warm by 1.0 degC too.
Willis says……..Dec15th 201 7.28pm
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Everything you say is IF there Willis. Did Micheal Moon say you worked as a massage therapist? Probably explains why you you were asking everybody for a bit of traction further up .
Frank,
“If anything in climate science desires to be called “settled science”, it might be radiative forcing.”
How is computed the CO2 forcing? By adding with a thought experiment some CO2 created ex nihilo. What is the temperature of this CO2? Obviously not defined. We uses the temperature profile of the atmosphere before the add but it’s a perfectly arbitrary operation. It is absolutely necessary to leave the new CO2 to adapt to its environment before making any calculation. Unfortunately, the principle of radiative forcing requires an instantaneous balance. This calculation is actually under-determined and the value obtained arbitrary.
We can being aware of that also considering the schematic equation of heat transfer through the atmosphere: Ts = L * P + k * P ^ 0.25 where Ts is the surface temperature, P the heating power, L and K synthetics factors. The addition of CO2 occurs in L and can not be modeled by an alteration of P. There is an exception with the energy evacuated directly from the ground and now intercepted by the added CO2 but it is a small amount.
“If the lapse rate remains unchanged, the surface will warm by 1.0 degC too.”
1 ° C may be correct as an average, by cons, we know that it’s not valid for surface because the main effect of the added CO2 is to change the lapse rate by reducing the potential radiative losses along the column.
This warming being not valid at the surface is critical because it is the surface temperature that initiates the feedback on water vapor.
Willis Eschenbach says, December 16, 2012 at 9:55 am: “While NET heat flow always goes from hot to cold as you claim, with radiation there are always two flows of energy going on. There is a flow of energy from the warmer to the cooler area, and there is also a flow of energy from the cooler to the warmer area. It is only the NET flow that is constrained to always go in one direction. Get a college-level beginner’s physics book, they’ll cover it in there. Here’s an example illustration, from the University of Sydney.”
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Willis, your illustration does illustrate an IDEA, but like any other illustration it does not prove the idea to be right or to be a scientific fact. You illustration only demonstrates that there are other people who share your idea about “NET”.
Second, and this is important, this “NET” thing makes physical sense with regard to temperature only, if “a flow of energy from the cooler to the warmer area”, as you put it, has an effect on the temperature of the warmer area. If it does not, your “NET” does not make physical sense at all.
Even if there is some effect on the temperature of the warmer area, but this effect is disproportionately or even vanishingly small, you can not just add or subtract energy and then derive temperature from the result of this arithmetic operation. This would be no science.
Which means, until this “NET” thing is not proven experimentally, it remains a pure fiction.
Please, Willis, present a clear reference to and a description of a REAL scientific experiment (not just a “thought experiment”) proving your idea about this “NET” effect.
Greg House says:
December 16, 2012 at 1:40 pm
Greg, I doubt you can find what you are asking for. Such basic statements are rarely accompanied by experiments. The fact that solid objects radiate depending on their temperature is such basic science that it is presented as a statement of fact rather than with an experiment.
Here is some information from MIT on exactly how to calculate the radiative heat exchange between two surfaces. They have no doubt that there are two separate radiative flows.
Now, if you don’t believe what the folks at MIT say about radiation, I’m afraid you’ll have to take it up with them.
w.
Willis writes “For TimTheToolMan and the others who think that downwelling longwave radiation can’t warm the ocean, not one single one of you has answered my simple question.”
I do think DLR slows the rate of cooling, Willis. I’ve told you this a number of times in the other thread. I’ve not said it doesn’t in this or any other thread so I dont know where that accusation keeps coming from.
I am pointing out they so far I believe your understanding on how the ocean warms as a result is lacking. You’ve stated that there is no difference between warming and slower cooling but then you’ve made statements that clearly indicate you believe the DLR increases the SST. Directly!. It does not. It cant because the ocean is cooling Willis. The sun warms it at depth, not at the very surface when, for example, clouds come over.
There IS a difference between slower cooling and warming because when you think “warming”, when you think more DLR means +100 W/m2 you can and do get it wrong.
Frank says:
December 16, 2012 at 11:11 am
I am clear that you can “do the calculations”, as you point out, to give a number for the IPCC-defined “climate forcing”.
The problem is, what you can’t do is measure, at any point in time and space, said climate forcing. So you can’t ever verify or validate your calculations, even in a rough sense. The thing being discussed (climate forcing under those conditions) doesn’t exist.
This means that whatever numbers you might come up with as you calculated “climate forcing” CAN NEVER BE FALSIFIED.
So yes, the IPCC definition has a clear meaning. The problem is that the clear meaning describes an impossible situation—they specify the climate forcing with the stratosphere responding and the troposphere and surface temperature held fixed, a situation which has never existed on the planet.
And that means that no statements about climate forcing can be falsified, and thus they are not scientific statements.
w.
Willis notes:
“Greg, I doubt you can find what you are asking for. Such basic statements are rarely accompanied by experiments. The fact that solid objects radiate depending on their temperature is such basic science that it is presented as a statement of fact rather than with an experiment.’
BUT, sir, I think I just gave you THE experiment (Phoenix vs. Atlanta). The amount of radiation from greenhouse gases seems to matter very little, if at all. Water and water vapor can probably explain it all.
I noticed that you have not responded to my last comment on this subject, and I am wondering why…
I don’t know anyone who disputes the fact that things with mass and temperature radiate (except perhaps Myrhh, I’m not sure what he or she thinks). The Kent drawing shows two independent sources radiating toward each other. No problem. Going further, I don’t know anyone disagreeing with the idea of a passive receptor heating up and radiating. The problem is trying to do useful work with re-radiated energy…and in the presence of convection? Good luck. You can’t get an average temperature increase of 33C from backward atmospheric re-radiation. Something this blatant would be easy to instrument in a lab environment.
kencoffman (@kencoffman) says:
December 16, 2012 at 4:36 am
And I, on the other hand, wonder exactly where you think the missing 340 W/m2 is coming from to keep the ocean liquid. Let me reprise the numbers for you:
ENERGY LOSSES FROM THE OCEAN
Radiation, ~ 400 W/m2
Conduction/convection of sensible heat, ~ 20 W/m2
Evaporative loss of latent heat, ~ 80 W/m2
TOTAL LOSSES, ~ 500 W/m2
So the ocean is constantly losing about half a kilowatt of energy per square metre on a 24/7 average basis.
Now lets look at the other side of the ledger:
ENERGY GAINS INTO THE OCEAN
Downwelling Solar Radiation (DSR), 160 W/m2
Downwelling Longwave Radiation (DLR), 340 W/m2
TOTAL GAINS, ~ 500 W/m2
Your claim that it is the sun sounds lovely, all full of sunshine and everything … but where are your numbers? You need to demonstrate mathematically, not just claim but demonstrate, that somehow the sun is delivering enough energy to keep not just the tropical ocean but the entire ocean liquid. If there is no DLR heating the ocean, that means that the sun must average half a kilowatt per square metre on a 24/7 basis …
Those are my calculations. I await your calculations as to how the sun is putting out half a kilowatt as a global 24/7 average …
And if you can’t do the calculations, I wonder about your analytical skill.
w.
kencoffman (@kencoffman) says:
December 16, 2012 at 4:36 am
Oh, yeah, Ken, one last point regarding your statement. If you just look at the tropics, it’s true there is more sun … but because the temperature is higher, there is also more evaporative, radiative, and sensible heat loss from the ocean. So the problem remains—the sun alone is not enough to keep it liquid.
w.
jae, you pointed out I haven’t answered the following, thanks:
jae says:
December 15, 2012 at 4:36 pm
Well, yeah … except that one of them is in the desert and one is not. As a result, they have very different responses to downwelling IR. There is an interesting discussion of these issues here.
w.
There seems to be some confusion about the idea of GHGs emitting IR which is absorbed at the surface, and heating it. It might be better to say, “transferring heat to the surface” rather than “heating the surface” because, at night, in the absence of other effects, the surface will inevitably cool, but will cool more slowly than without the GHGs. During the day, the surface is warmed by the sun.
The whole climate change issue involves questions of whether the Earth might warm, on the average, by 2 degrees C over the next century, or by 3 degrees, perhaps 5 degrees, or by 1 degree or less, with various consequences or lack thereof.. This projected temperature change, over a century, is superimposed on daily and seasonal changes. Daily changes of 10 degrees is quite ordinary, and seasonal changes of 30 degrees or more are quite common, as compared to a much smaller AVERAGE change over 100 years.
There is NO need to worry about where the heat would come from for global warming; it comes in every day. If the Earth were to heat up, on the average, by 10 degrees C over the next century, most climate scientists think that truly cataclysmic results would follow–but NOBODY thinks that this is a remotely serious possibiltiy. The balance between incoming and outgoing energy is fine enough that one day’s sunlight changes the temperature much more than any average change that anyone seriously considers for the next century. (Heating the top layers of the oceans would take more than a day, but still much shorter than a century.)
GHGs do indeed radiate IR to the surface and transport heat thereby. But the surface cannot actually warm from this unless the atmosphere is actually warmer (which could happen if, say, a warm front moves through). But the effect of GHGs is to slow the rate at which the surface cools through IR emission. The actual mechanism is complicated, but that’s the end result.
We could try to calculate the temperature at the surface in terms of how much the atmosphere radiates to the ground, various heat capacities, etc. but that’s difficult to conceive of, and difficult to solve. There’s an easier way: despite the differences of night and day, seasons, weather, etc. the incoming and outgoing energy is always very close to balanced. Were this not so, the average temperature would go up, not over a century, but over a matter of weeks or days. It would probably be very exciting. But the main regulatory mechanism, the sharp dependence of IR emission on temperature, puts the brakes on quickly. As Frank mentioned above, emission goes as the fourth power of temperature. For every 1% increase in absolute temperature, which is about 3 degrees C, there’s about a 4% increase in IR emission. So, if nothing else has changed, that cools the surface down pretty quickly. (For a demo, wait until sunset.)
So, to solve it the easy (or easier) way, we look at the percentage of IR that gets through (at each wavelength, it’s not quite simple) and then ask: what temperature would the surface have to be so that the heat that escapes through IR in 24 hours is equal to the heat received from the sun in one day? The more the GHGs “block” the IR the higher that temperature is. The word “block” is a gross oversimplirication, but in the end, that’s why the temperature goes up–more solar heat is retained, until the surface is warm enough to shove through an amount of energy that equals, on the average, what the sun puts in.
Of course, after that, you look at the IR absorption spectra of the greenhouse gases, blackbody emission spectra, heat transport through air, currents, ocean currents, evaporation, precipitation, thermals caused by politicians emitting large amounts of hot air…lots of complications. But one thing you DON”T have to worry about is how the energy gets to the ground to heat it up. The sun takes care of that, every day.
TimTheToolMan says:
December 16, 2012 at 5:35 pm
Tim, I find this insistence on some meaning of “warming” is semantical quibbling. For example, we say that putting on a jacket warms us up. Now, in fact all it does is slow down the cooling.
So what? The result is the same, so what is the difference? We end up warmer when we wear a jacket than when we don’t. The ocean ends up warmer when there is DLR than when there is no DLR.
Again, I find this to be semantic nonsense. The DLR slows the evaporation at the surface. As a result, the bulk of the mixed layer ends up warmer than it would be in the absence of DLR. So yes, DLR does indeed increase the SST down deep in the ocean.
In fact, there is absolutely no difference between warming and slower cooling. Suppose I have a warm block of iron, losing energy at some rate X.
I put a blanket on it, in an hour it may only experience half the temperature drop it experienced when it had no blanket.
Then I run the experiment again. Instead of a blanket, I put propane torches on all sides of it to warm it perfectly evenly. As a result it only experiences half the temperature drop it experience when it had no blanket.
Here’s the thing. There’s no difference in result between the blanket and the torches. If someone warmed it one way or the other in secret, you couldn’t tell the difference. The final temperature is the same, the amount of heat in the block of iron is the same.
So it doesn’t matter to me in the slightest whether you call it “warming” or “slowing the cooling”. The end result is the same, the bulk of the mixed layer is warmer with DLR than without DLR.
Finally, this again is like trying to prove that people can’t climb the mountain, when we can clearly see people who have climbed to the top … your problem is to figure out where the missing 340 W/m2 is coming from.
w.
Willis Eschenbach says:, December 16, 2012 at 5:23 pm: “Greg, […] The fact that solid objects radiate depending on their temperature is such basic science that it is presented as a statement of fact rather than with an experiment.
Here is some information from MIT on exactly how to calculate the radiative heat exchange between two surfaces. They have no doubt that there are two separate radiative flows.
Now, if you don’t believe what the folks at MIT say about radiation, I’m afraid you’ll have to take it up with them.”
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Willis, I am not questioning the fact that solid objects radiate depending on their temperature, or that there are separate radiative flows. You have probably misunderstood the point. I am questioning the alleged effect of radiation from colder bodies on TEMPERATURE of warmer bodies, and logically the calculations of what you call “NET” transfer. I hope you have understood the point now.
Your references to “folks at MIT” are not a scientific argument unfortunately, anyway not when the very essence of your point is questioned. It is a wide spread logical fallacy called “appeal to authority”. I am very sure that “folks at MIT” can give references to other “folks” and so on. Such a circle of references is, however, not a scientific argumentation.
You are apparently a knowledgeable man, so I guess, if you can not refer to a real scientific experiment confirming your (and other “folks’) assertion about that “NET” thing, you probably are capable of understanding that this assertion can not be considered a scientific fact, it is just a fiction.
So here’s a stab at explaining why the oceans don’t freeze for lack of DLR:
Take a water heater and remove the dip tube. Install a big pump that recycles water between the holes at the top of the tank. What you are doing is installing a flowmeter and thermometer on the outflow side and saying, “Wow, there is so much energy leaving this thing would freeze if it weren’t warmed by water coming back in.”…
Willis writes “Here’s the thing. There’s no difference in result between the blanket and the torches.”
You’ve made another strawman argument without even realising it… The thing is that DLR (and a blanket) redirects the object’s energy back at the object. Back radiation. And its just not possible for a blanket to make the block of iron warmer than when you started. Just because you can set a propane torch up to account for the same energy loss means nothing and doesn’t mean warming is the same as cooling.
Do you stand by this statement that you made to tallbloke?
“The very surface warms … until it’s slightly warmer than the bulk … which then heats up slightly, until the surface is slightly cooler than the bulk, and the previous condition (cooler surface) is restored.”
Because this is very explicitly saying that DLR can warm the ocean warmer than it was before you started. This is like saying I can put a blanket on the iron or put coffee in a thermos and it will get warmer than when I started.
Willis says this: ‘Regarding heat flow, you are missing the boat entirely. While NET heat flow always goes from hot to cold as you claim, with radiation there are always two flows of energy going on. There is a flow of energy from the warmer to the cooler area, and there is also a flow of energy from the cooler to the warmer area. It is only the NET flow that is constrained to always go in one direction. Get a college-level beginner’s physics book, they’ll cover it in there. Here’s an example illustration, from the University of Sydney.’
This is plain wrong. Unfortunately most people are taught it as if it’s correct. The reason is they are taught the S-B equation and the difference, net energy flux is the difference between the two S-B predictions. This is incredibly misleading though and you along with most have fallen in to the trap.
To prove this you go back two steps in the physics. The first is the Planck Irradiation Function which when integrated over the wavelengths or the wave numbers is the S-B equation. The second is to understand the the PIF at any wavelength/wave number is for a collimated beam identical to the Poynting Vector. This transfers to physics to Maxwell’s Equations.
The wonder of this is Poynting’s Theorem which is that the net PV at any point in space is the vector sum of all the arriving PVs. In other words there can never be two streams doing work. Only the vector sum at a point can do work.
This is why the climate models are total, absolute bunkum. You can’t compute absorption of energy from the two streams because it exaggerates warming by a factor of ~7. What’s more as there is zero net CO2 IR emitted from the surface [basic radiation physics at thermal equilibrium means net PV is zero where the two PVs are near black body iamplitude] there can never be any CO2-AGW or positive feedback.
Please Willis, learn the real physics and tell these IPCC charlatans they have got it wrong. It goes back to Houghton using the two-stream approximation to calculate energy absorption. If he had had the scientific wit to work out that the DOWN warming is negative to offsets most of the UP warming we might have avoided this incredible mess of fake science.
I shall also add a point I haw made in the past which is that the belief in DLR is entirely baseless because a pyrgeometer measurement is the artefact of the instrument’s shielding. The proof it to have two pyrgeometers back to back in zero temperature gradient – net signal = 0. Take one away and the signal jumps to a measure of the S-B flux for that body at its particular temperature and emissivity.
However, until that electromagnetic wave combines destructively with the wave from the opposite direction, it cannot do any thermodynamic work. ‘Back radiation’ is an imaginary energy flow all of which is destroyed at the Earth’s surface. The only work that can be done from the Earth’s surface is the 63 W/m^2 net IR flux, the 17 W/m^2 convection and the 80 W/m^2 evapo-transpiration.
Anyone who claims differently has to justify it from Maxwell’s Equations and they can’t.
Greg House says:
December 16, 2012 at 10:22 pm
Greg, thank you for your explanation. Now, I see that in fact you agree that everything radiates.
It appears that you believe, however, that when radiation from something cooler is absorbed by something warmer than the spot where the radiation originated, no energy of any kind is transferred to the warmer object.
Is this in fact your belief? And if so … where does the energy go that was contained in the radiation? It can’t vanish. It’s not reflected. I say that energy is converted to heat. If I understand you, you say it is not converted to heat … so what is the energy converted into?
As I said above, there’s plenty of things in science for which you won’t find published experimental results, because they are too basic. If you are dead-set on an experiment, here’s one for you. You can do it as a thought experiment, or as a real experiment if you wish.
Put a 100-watt incandescent bulb in a fixture, turn it on and let it equilibrate, and measure the temperature.
Put a 40-watt incandescent bulb in a fixture, turn it on and let it equilibrate, and measure the temperature.
Clearly, at equilibrium the 100-watt bulb will be hotter than the 40-watt bulb.
Now, for the final test, put the 100-watt and the 40-watt bulbs in full view of each other (but not so near as to allow heating by conduction/convection), turn them on, and let the whole setup equilibrate.
So here’s the point of the experiment. What do you think the final temperatures of the bulbs will be when both are lit?
a) Both bulbs will be the same temperature as when they were lit individually.
b) Both bulbs will be cooler than when they were lit individually.
c) The 100-watt bulb will be warmer, and the 40-watt bulb will be the same.
d) The 40-watt bulb will be warmer, and the 100-watt bulb will be the same.
e) Both bulbs will be warmer.
Me, I can do it as a thought experiment, I don’t need to build the apparatus to be clear about what will happen. YMMV.
All the best,
w.
PS—Were I in your shoes, I’d study what the folks at MIT say in the citation I referenced. I’d study it until I understood what they were saying, inside and out. Then I’d see if I could find theoretical or practical problems with their explanation before I advanced my own theory on how the world works … but hey, that’s just me.
And no, this is not an “appeal to authority”. Instead, it is an appeal to investigate what the authorities have to say before striking out on your own. Some very bright people have given these questions some very profound thought, and it behooves us to investigate their contributions thoroughly in order to have a firm base for our understanding.
And perhaps eventually, to expand or even overthrow their profound thoughts … but to do that, first you have to understand them.
But like I said, that’s just me …
Folks, I’ll say it again. “Proving” that the DLR (downwelling longwave radiation) can’t heat the ocean is meaningless in this discussion. All of your convoluted explanations are wasted on me.
I have asked a simple question.
Simple energy calculations show that the incoming sunlight at the surface (global 24/7 average ≈ 160 W/m2) is not enough to balance the known losses from radiation, conduction/convection, and latent heat loss (global 24/7 average ≈ 500 W/m2). The calculation is out of balance by about 340 W/m2. I (and most every scientist I know of) say that this 340 W/m2 is the energy that the ocean is absorbing from the DLR.
Until someone can come up with an alternate source for the missing energy (about 340 W/m2), I’m going to just keep on saying it is supplied by the DLR. I’m sorry, but I have to deal with the reality that the oceans are not frozen. The geothermal heat flux is about three orders of magnitude too small to supply the missing energy necessary to balance the oceanic energy budget. I know of no other source of energy that would keep it liquid. Nor has anyone else identified one.
I add to that the fact that downwelling longwave radiation is known to heat what it is absorbed by; the fact that DLR is absorbed by the ocean; the fact that DLR has been experimentally measured all around the world in a variety of seasons, times of day, and locations; and the fact that the energy contained in the DLR is of the right size (about 340 W/m2) to supply the missing energy to the ocean.
Now, y’all can believe in rainbow energy or pyramid energy or whatever, I don’t care. But until someone can come up with an alternate source of 340 W/m2 of energy to keep the ocean liquid, I’m calling BS on the claim that the ocean is not warmer with DLR than it would be without it.
Willis: The citation you reference, about radiative heat transfer calculations, is exactly what I was taught as a Metallurgical Engineer. Until 3 years’ ago when I set out to study exactly what the IPCC claimed, I have never thought beyond the S-B analysis. However, once I realised the climate models have in them a perpetual motion machine, creating much more IR energy to be absorbed than real net IR, I decided to find out why.
The two-stream approximation cannot be used to calculate heat absorption unless one stream is defined as negative, the cooler to the warmer. You cannot have a perpetual motion machine. Unfortunately, the grant money would disappear because the CAGW scare vanishes, and we can’t have real science interfering with capitalism, can we?
Dec 14th @10.34 am “So what is providing…….. energy that is keeping the ocean from freezing? I keep waiting and waiting for you folks to say it is not DLR to explain why the oceans are not frozen” (then later)… “where is the energy coming from to keep them unfrozen?”
So then he ,Willis (hopefully) reads what I said to him about Trenberth’s unreal geometrically derived IPPC crap of 160w/sq.m. reaching the Earths surface. But no he persists..2 days later..
Dec16th 2012 @6.38pm “So the problem remains- the sun alone is not enough to keep it liquid”.
You know how you might be reading something right in front of you but cannot believe what your eyes are seeing. This is exactly my case here. How can this guy Willis who calls himself a scientist (maybe that’s his problem) say such stuff.
Willis…
If you were to take the earth and for hypothesis sake freeze the seas. Then introduce a sun which will apply a continuous and timeless input of energy to the surface of 340w/sq.m. I’m sure that before too long we would approach what we have today in reality. I’m going to say this again Willis without any smilies or winkies . It’s the sun stupid.
Willis: ‘If DLR is not keeping the ocean from freezing, what is?’
The answer is very simple. The oceans do not emit 400 W/m^2 ULR. The only IR they emit is the net 60 W/m^2. This is an inescapable fact – only net energy flows are real.